Preparation of anatase-type TiO2 nanocrystal/acetylene black composites by a dry process, and their electrochemical lithium insertion

作者：Tang WP^*

来源：Journal of Materials Chemistry, 2004, 14(23): 3457-3461.

DOI：10.1039/b405249h

Composites consisting of anatase-type TiO2 nanocrystals/acetylene black were synthesized by a novel dry process, involving only the grinding of a mixture of titanium tetraisopropoxide and acetylene black in air for natural hydration, followed by heating. The effects of heating temperature on the formation and properties of the nanocomposite were investigated. The TiO2 nanocrystal/acetylene black composites could be produced at a temperature of less than 500degreesC, with the content of acetylene black decreasing with increasing heating temperature. A single phase of anatase-type TiO2 could be obtained in the composites at a temperature of less than 400degreesC, with the addition of a very minor rutile phase at 500degreesC. The crystallization and the size of TiO2 nanocrystals increases and the dispersion decreases with an increase in the heating temperature. The sizes are 10, 13 and 18 nm for the products at 300, 400 and 500degreesC. The amount of lithium inserted in the 1st discharge process depends on the size of the TiO2 nanocrystals as well as on their crystallization and dispersion. The product obtained at 400degreesC gives the highest amount of lithium insertion, having Li/Ti = 0.95 in the solid, and the cell has a markedly high capacity of 319 mAh g(-1) at a cutoff voltage of I V. The voltage in the discharge curve showed a flat plateau around 1.8 V until Li/Ti = 0.4 after which it decreased. The electrochemical lithium insertion progressed topotactically, even with a large amount of lithium insertion, without any structural change.

• 出版日期2004-12-7